The present invention relates to a tidal current generator. In detail, the present invention relates to a tidal current generator that can efficiently generate power by separating an on-water power generation unit and an in-water power collection unit, that allows for easy management of facilities on the water because the facilities in the water can be easily pulled up on the water even if they break, that can maximally use the flow of tides using a connection rope and a groove formed on a rotary propeller, and that can maximize efficiency by controlling the number of power connections between a rotary unit and an on-water power generator in accordance with the states of the flow of tides to prevent waste or deficit of power transmission.
Power generation systems for generating electricity are being implemented in a wide variety of ways. In case of a thermal power generation, a fossil energy etc. is used to cause serious environmental pollutions. In case of a nuclear power generation, there are many risk factors such as a storage of nuclear waste etc. and a possibility of explosion thereof.
On the other hand, a wind power generation and a photovoltaic power generation, which are getting the spotlight as a renewable energy, are heavily influenced by weather. In case of the wind power, it cannot generate electricity from wind unless the wind blows. Also, it is difficult to forecast the occurrence of wind. In case of the sunlight, it cannot generate electricity from solar heat in the dark or the rain or at night.
In comparison, the tidal current power generation, which is a marine power generation, has a very short history and a predominant power generation model has not yet appeared. However, it is a very attractive clean energy technology in that it is predictable and can be operated 24 hours a day, except for a certain time.
Unlike the tidal power generation of generating electricity by using a head of water through tidal dams, in the tidal current power generation, water turbine generators are installed at the points where tidal currents are fast and the installed water turbine generators are driven by using natural tidal current to generate electricity.
Therefore, since only the water turbine generators required for power generation without the tidal dam are installed, it costs less. On the contrary, it is difficult to select the right place and the power generation thereof depends on the intensity of the natural flow of the tidal current. In terms of environment, the flow of seawater is free and has little impact on the marine environment, so it is considered to be more environment-friendly than the tidal power generation.
The tidal current power generation, like the wind power generation, uses the kinetic energy of a fluid to generate electricity by rotating the turbines, except that the flow of seawater is used instead of the wind. The tidal current power is more attractive than the onshore wind power because the density of seawater is about 840 times larger than that of air. Accordingly, the size of a turbine of the tidal current is generally much smaller than that of a wind turbine at the same capacity. Generally, the energy generated by the fluid flow increases exponentially with the flow rate, and therefore, a place having a large flow rate is absolutely advantageous for tidal current power.
Despite these advantages, in the conventional tidal current generator system, there has been a disadvantage in that it cannot be easily repaired when facilities such as a rotating propeller (blade) or a connecting bearing and so on located in the water are broken. This is because the facilities are constantly rotated by strong tides in the water, making it difficult for workers to approach them.
In addition, in the conventional rotary propeller structure, since a large amount of vortex is generated in the sectional area of the portion of generating the driving force and the flow of the tidal current cannot be properly received, there is a problem in that the efficiency thereof is lowered. Also, the flow of the tide current is continuously changed according to the situation and terrain thereof, and the power generation efficiency is not stable at that time. Accordingly, the overall productivity of the tidal generator is not good.